centos7使用的MariaDB，替代了早期版本默认的MySQL。MariaDB是MySQL的一个分支，由开源社区维护，采用GPL授权许可，且MariaDB完全贱人MySQL。
检查centos7下现有的MariaDB安装包：
[hadoop@hadoop01 ~]$ rpm -qa| grep mariadb
mariadb-libs-5.5.60-1.el7_5.x86_64
删除MariaDB安装包：
[hadoop@hadoop01 ~]$ su root
Password:
[root@hadoop01 hadoop]# rpm -e --nodeps mariadb-libs-5.5.60-1.el7_5.x86_64
下载mysql安装包：
mysql-8.0.17-1.el7.x86_64.rpm-bundle.tar
注：要对应各自centos的版本，我用的是centos7
检查是否安装其他mysql包：
rpm -qa | grep mysql
安装mysql：
rpm -ivh mysql-community-common-8.0.17-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-8.0.17-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-8.0.17-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-8.0.17-1.el7.x86_64.rpm
成功结果：
[root@hadoop01 hadoop]# rpm -ivh mysql-community-common-8.0.1
warning: mysql-community-common-8.0.17-1.el7.x86_64.rpm: Head
Preparing... #######################
Updating / installing...
1:mysql-community-common-8.0.17-1.e#######################
[root@hadoop01 hadoop]# rpm -ivh mysql-community-libs-8.0.17-
warning: mysql-community-libs-8.0.17-1.el7.x86_64.rpm: Header
Preparing... #######################
Updating / installing...
1:mysql-community-libs-8.0.17-1.el7#######################
[root@hadoop01 hadoop]# rpm -ivh mysql-community-client-8.0.1
warning: mysql-community-client-8.0.17-1.el7.x86_64.rpm: Head
Preparing... #######################
Updating / installing...
1:mysql-community-client-8.0.17-1.e#######################
[root@hadoop01 hadoop]# rpm -ivh mysql-community-server-8.0.1
warning: mysql-community-server-8.0.17-1.el7.x86_64.rpm: Head
Preparing... #######################
Updating / installing...
1:mysql-community-server-8.0.17-1.e#######################
mysql启动关闭状态：
[root@hadoop01 hadoop]# service mysqld start --启动
Redirecting to /bin/systemctl start mysqld.service
[root@hadoop01 hadoop]# service mysqld stop --关闭
Redirecting to /bin/systemctl stop mysqld.service
[root@hadoop01 hadoop]# service mysqld status --查看状态
Redirecting to /bin/systemctl status mysqld.service
● mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: inactive (dead) since Tue 2019-09-17 01:23:32 CST; 24s ago
Docs: man:mysqld(8)
Process: 9334 ExecStart=http://www.likecs.com/usr/sbin/mysqld $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
Process: 9247 ExecStartPre=http://www.likecs.com/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
Main PID: 9334 (code=exited, status=0/SUCCESS)
Status: "Server shutdown complete"
Sep 17 01:17:08 hadoop01 systemd[1]: Starting MySQL Server...
Sep 17 01:17:19 hadoop01 systemd[1]: Started MySQL Server.
Sep 17 01:23:30 hadoop01 systemd[1]: Stopping MySQL Server...
Sep 17 01:23:32 hadoop01 systemd[1]: Stopped MySQL Server.
首次登陆获取自动生成的临时密码：
[root@hadoop01 hadoop]# sudo grep \'temporary password\' /var/log/mysqld.log
2019-09-16T17:17:17.183833Z 5 [Note] [MY-010454] [Server] A temporary password is generated for root@localhost: ?jeVxKndj40d
[root@hadoop01 hadoop]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.17
Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type \'help;\' or \'\h\' for help. Type \'\c\' to clear the current input statement.
mysql> --到此成功登陆mysql，下面我们需要修改root账户的登陆密码才能进行数据库相关操作。 --修改密码命令：ALTER USER \'root\'@\'localhost\' IDENTIFIED BY \'MyNewPassword\' 创建授权删除查询新用户： mysql> create user \'User\'@\'localhost\' identified by \'User_123456\'; --创建 Query OK, 0 rows affected (0.02 sec) mysql> grant all privileges on *.* to \'User\'@\'localhost\'; --授权 Query OK, 0 rows affected (0.02 sec) mysql> drop user User@localhost; --删除 Query OK, 0 rows affected (0.01 sec) mysql> select user,host from mysql.user;--查询 +------------------+-----------+ | user | host | +------------------+-----------+ | mysql.infoschema | localhost | | mysql.session | localhost | | mysql.sys | localhost | | root | localhost | +------------------+-----------+ 4 rows in set (0.01 sec) 我们进行如下操作： mysql> create user \'User\'@\'localhost\' identified by \'User_123456\'; Query OK, 0 rows affected (0.01 sec) mysql> grant all privileges on *.* to \'User\'@\'localhost\'; Query OK, 0 rows affected (0.01 sec) mysql> create user \'User\'@\'%\' identified by \'User_123456\'; Query OK, 0 rows affected (0.01 sec) mysql> grant all privileges on *.* to \'User\'@\'%\'; Query OK, 0 rows affected (0.01 sec) mysql> create user \'User\'@\'master\' identified by \'User_123456\'; Query OK, 0 rows affected (0.01 sec) mysql> grant all privileges on *.* to \'User\'@\'master\'; Query OK, 0 rows affected (0.02 sec) mysql> select user,host from mysql.user; +------------------+-----------+ | user | host | +------------------+-----------+ | User | % | | User | localhost | | mysql.infoschema | localhost | | mysql.session | localhost | | mysql.sys | localhost | | root | localhost | | User | master | +------------------+-----------+ 7 rows in set (0.00 sec) mysql数据库的基本操作： mysql> create database test_db;--创建数据库 Query OK, 1 row affected (0.01 sec) mysql> show databases; --展示数据库 +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | | test_db | +--------------------+ 5 rows in set (0.07 sec) mysql> use test_db; --进入数据库 Database changed mysql> create table myclass ( --创建数据表 -> id int(4) not null primary key auto_increment, -> name char(20) not null, -> sex int(4) not null default \'0\', -> degree double(16,2)); Query OK, 0 rows affected, 3 warnings (0.04 sec) mysql> insert into myclass values(0001,"Liu Qin Jiang",0,100.00); --插入数据 Query OK, 1 row affected (0.02 sec) mysql> select * from myclass; -查询数据 +----+---------------+-----+--------+ | id | name | sex | degree | +----+---------------+-----+--------+ | 1 | Liu Qin Jiang | 0 | 100.00 | +----+---------------+-----+--------+ 1 row in set (0.00 sec) mysql> drop table myclass; -删除数据表 Query OK, 0 rows affected (0.03 sec) mysql> drop database test_db; --删除数据库 Query OK, 0 rows affected (0.02 sec)